Progression-free survival, patient-reported outcomes and the Holy Grail

In oncology clinical trials, overall survival (OS) remains the gold standard for clinical beneft. However, because there are so many available treatment options for most types of cancer, survival analysis in clinical trials is often confounded by subsequent therapies. Progression-free survival (PFS) is an endpoint not so confounded, and one that requires fewer patients and less time to arrive at a conclusion about a new therapy. As a result, an ever-increasing number of oncology clinical trials are launched in which PFS is used as the primary endpoint. Several years ago, Pazdur emphasized that the time-to-progression endpoint must use the same evaluation techniques and schedules for all treatment arms and he recommended blinding of trials or at minimum, the use of an external blinded radiographic review committee. He also noted that improvement in disease-related symptoms qualifes as clinical beneft and may therefore be an appropriate endpoint for drug approval.